How do I Automatically Foward Calls to Bluetooth?

I have a very specific case, that can probably be fixed by a general setting that I do not know about.
I have a HOT Smart watch, that allows me to control the Cortana on my phone from the watch using the watch's speaker and microphone. When I make a call from the watch, by asking Cortana to call [person], the call is on my phone's speaker and microphone, not the watch's. Is there a way that when I make a call, or tell Cortana to make a call it will automatically send my call to Bluetooth, without me having to take out my phone and manually click the Bluetooth button? It is quite annoying right now, and defeats the purpose of calling people using Cortana from the watch.